DNA barcodes reveal environmental secrets

A view of rhino drinking at the waterhole.


Finding bad guys via DNA is no longer restricted to the world of the FBI, popular novels or television series like CSI. Now the newfound scientific power to quickly "fingerprint" species via DNA is used to convict rhino poachers in South Africa, unmask fake herbal medicines and expose what eats what in nature among other applications across a wide range of public interests.

All these new uses of DNA "barcoding" - identifying species based on a snippet of DNA - were on the agenda at the 4th International Barcode of Life Conference which took place at Australia's University of Adelaide from November 28 to December 3, 2011.

DNA Barcoding has been the topic of a number of studies the last few years and hot new applications include:

Convicting rhino poachers in South Africa

Dr Cindy Harper, Head of Veterinary Genetics Laboratory (VGL) at the Faculty of Veterinary Science at the University of Pretoria in South Africa started a research project to extract DNA from rhino horn in 2007. She found that the DNA taken from a specific rhino horn can match DNA found on any other part of the rhino or its carcass. This meant that when a rhino horn is found in the possession of a poacher, DNA can link it to a carcass found in the veld, which can lead to a conviction.

Since then, the faculty of Veterinary Services of the University of Pretoria has developed 1 000 DNA kits, which were handed over to the South African National Parks (SANParks) earlier this year for use in its anti-poaching campaign, especially when facing poachers in court. This year, up to mid-December, 244 rhinos had been killed in the Kruger National Park (KNP).

What eats what

DNA barcoding can distinguish species contained in the gut or dung of animals, revealing what eats what. University of Adelaide researcher Hugh Cross, presented his investigation into the diet of Australia's fast-growing, one million-strong population of wild camels, which severely impact the country's ecology, at the conference. Introduced in the 1800s as pack animals, Australia's wild camels eat an estimated 80 percent of available plant species in their range.

The blood meals of biting insects

Resembling a common housefly, the African tsetse fly transmits Human African trypanosomiasis, also known as sleeping sickness, to people and animals. One of the world's most dangerous disease vectors, it spread the 2008 epidemic in which 48,000 Ugandans died. And the annual economic impact is estimated at R36,7 billion, with around three million cattle killed every year.

Scientists are using DNA barcodes to identify tsetse fly species and their prey based on analysis of the insect's blood meals, unravelling the relationship between hosts and vectors.

By developing the barcode library, tools and ability to readily distinguish species of tsetse flies, mosquitos, ticks and other vectors of diseases such as malaria, leishmaniasis, schistosomiasis, Japanese encephalitis, and Lyme disease, scientists can map risk areas more efficiently and alert authorities to the spread of health threats.

Barcoders have taken up an ambitious five-year goal to establish a comprehensive library of 10,000 insect species that damage or destroy so many human lives: 3,000 mosquito, 1,000 sandfly, 2,000 blackfly, 2,000 flea and 1,000 tick species.

Nemo and friends

According to scientists, over one billion ornamental fish, comprising more than 4,000 freshwater and 1,400 marine species, are traded internationally each year, a R40 billion industry growing annually at eight percent. Researchers at work on this issue include Gulab Khedkar of India, who says: "To facilitate ornamental fish trading, and in compliance of (India's) Biodiversity Act, a universal method must validate the ornamental fish with their species names. This can help assure a sustainable ornamental fish trade."

Insect pollinators

The ecosystem service of plant pollination by insects has a global value estimated at more than R5100 billion a year. Facilitated by the International Barcode of Life (iBOL), barcoders are surveying long-term population trends by assembling barcode libraries for all bees and other important pollinators - flies and beetles. In combination with campaigns to barcode moths, butterflies and birds, they will provide the database needed to assess the state of pollinator communities worldwide.

The Barcode of Life Database

Scientists in Adelaide and others around the world are working towards an international library of barcodes for 500,000 plant, animal and fungi species within five years. The Barcode of Life Database includes more than 167,000 reliably named and provisional species today. Butterflies and moths are the largest well-analysed group so far, with over 60,000 named and provisional species.

At the Smithsonian Institution's National Museum of Natural History, another team recently barcoded over 3,000 frozen bird tissues from over 1,400 species, adding more than 500 new species to the world avian DNA library, now covering about 40 percent of known birds.

New techniques for DNA extraction are bringing older and older specimens in natural history museums into the age range where DNA barcoding can be effective. These breakthroughs will open up new research questions about changes in species over the past centuries of human impact on natural populations.

The Munich Botanical Garden is the latest institution with an important collection of authoritative reference specimens opening its collection to a DNA barcode blitz.

The ability to identify and distinguish known and unknown species ever more quickly, cheaply, easily and accurately based on snippets of DNA code grew from a research paper in 2003 to a burgeoning global enterprise today, led by the Consortium for the Barcode of Life (CBOL) at the Smithsonian Institution.

In 2005, there were 33,000 records covering 12,700 species in the Barcode of Life Data Systems (BOLD) at the University of Guelph, Canada. Showing a more than 40-fold increase, almost 1.4 million records are now banked, representing roughly 167,000 known and provisional species (see www.barcodinglife.org/views/taxbrowser_root.php).

The Consortium for the Barcode of Life (CBOL) develops DNA barcoding as a global standard for species identification. With more than 200 member organizations from more than 50 countries, CBOL builds global participation, sets community standards, and organizes and supports working groups, workshops, networks, training opportunities, and international conferences held every two years. Free and open to all, CBOL promotes general awareness of barcoding through an information website (www.barcodeoflife.org) and information sharing through Connect (http://connect.barcodeoflife.net), the Barcode of Life social network.



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